If directed too far upward, the light beam projected from the automotive headlamp will dazzle the driver of a car running in the opposite lane, possibly causing a danger. On the contrary, if directed too far downward, the headlamp will not provide a sufficient illumination of the road in front of the car for assurance of safe driving. Therefore, the automotive headlamp must be provided with a device which is fixed on the car body for fine adjustment of the optical-axis in the vertical direction.
A typical one of the automotive headlamps of this type is known from the disclosure in the U.S. Pat. No. 5,055,980, in which a to-be-adjusted body is pivotably mounted on a mount body by means of a pivot bearing, a lamp bulb is fixed to the to-be-adjusted body, and a device for adjusting the optical axis in the vertical direction is fixed between the to-be-adjusted body and the mount body. The vertical optical-axis adjuster is operated to pivot the to-be-adjusted body vertically with respect to the mount body for adjustment of the optical axis in the vertical direction.
The above-mentioned automotive headlamp is provided with a right/left or horizontal optical-axis adjuster in addition to the vertical optical-axis adjuster. The horizontal optical-axis adjuster can be operated to pivot the to-be-adjusted body horizontally with respect to the mount body for adjustment of the optical axis in the horizontal direction.
The above-mentioned automotive headlamps include two types. In one of these two types, the reflector is movable, and the reflector as the to-be-adjusted body is pivotably mounted on a lamp housing as the mount body. In the other type, the lamp unit is movable, and the lamp unit as the to-be-adjusted body is pivotably mounted on the car body as the mount body.
The direction of the optical axis must be adjusted with a high accuracy and can be adjusted accurately only by a specialist using a special equipment. Before shipment from the automobile manufacturing works or when the headlamps are equipped on a car at an adjustment shop, the optical axes of the head lamps are adjusted by the specialist with the special equipment. If the optical axis of the headlamp of a car is found deviated from its due direction for any reason after adjusted at such works or shop, it must be readjusted.
However, some reference is available for such readjustment. Namely, since the optical axis of the headlamp has already been adjusted accurately, it can be readjusted without any special equipment and specialist by reproducing its initial state of adjustment. For this purpose, there have been proposed various kinds of optical-axis adjustment confirming devices (more specifically, devices for confirming whether the initially adjusted state of the optical axis has been reproduced or not) designed based on such a concept.
A typical one of such devices is disclosed in the aforementioned U.S. Pat. No. 5,055,980.
This conventional optical-axis adjustment confirming device comprises a horizontal extension formed on the to-be-adjusted body thereof, a casing fixed indirectly to the horizontal extension by means of a leaf spring or the like or directly to it with a screw or the like, a bubble tube, a cover supporting the bubble tube at the rear side thereof and of which one end is engaged on one end of the casing, and a spring and adjusting screw used to fix the other end of the cover vertically tiltably to the other end of the casing.
After completion of the optical-axis adjustment by the specialist using the special equipment, the optical-axis adjustment confirming device is initially set by turning the adjusting screw for the bubble in the bubble tube to come to the reference line (zero point on the scale). When the optical axis of the headlamp is considered to have been directed in a wrong direction as caused by a remodeling of the car body or loading of the car, the position of the bubble in the bubble tube is visually checked with the car kept stopped on a horizontal floor or ground surface. If the bubble is found not coincident with the reference line, it means that the vertical direction of the optical axis is deviated from a correct one. In this case, it sufficient to tilt the to-be-adjusted body vertically, for the bubble to be coincident with the reference line, by operating the vertical optical-axis adjustment confirming device while watching the movement of the bubble in the bubble tube. By this operation, the optical axis will restore its accurately adjusted initial vertical direction.
The present invention has an object to provide a device for confirming the optical-axis adjustment of an automotive headlamp in which the initial setting mechanism of the level is composed of a reduced number of parts, can be easily installed and also the initial setting of the level can be adjusted very easily.